The present invention relates to the field of gauging devices and is more particularly concerned with a muscle strength testing method and apparatus allowing simultaneous assessment of the muscular contraction of a selected muscle through direct contact between an examiner and a patient and assessment of the strength of the muscular contraction of the selected muscle through the use of a pressure sensor.
Muscle strength can be defined as the ability of a muscle or a group of muscles to produce tension or exert force through the skeletal system. The generally accepted measurement criterion for the maximum tension which can be exerted by a muscle is the maximum amount of force a muscle can exert on a body part. In physiology, this is referred to as the maximum strength of the muscle and might be expressed, for example, in kilograms per square centimeter of muscular section. In day-to-day life with the patient, the strength is usually expressed in kilograms, Newtons, pounds or inch-pounds and Newton-meters.
There are a plurality of situations wherein it is desirable to monitor or test different muscle strength of an individual. This type of examination is commonly used in diagnostic, therapeutic and prevention activities. The tests are typically used to determine difference in strength between individuals and/or to determine strength deficits in a given individual. In such a case, deficits are detected by the comparison of contralateral limb segments or muscle groups. The tests are also typically used to monitor a patient""s progress during a period of recovery or rehabilitation. Muscle testing is also used in the design of rehabilitation programs for injured patients or individuals wanting to undertake activities for which they are not properly conditioned.
Although the medical and therapeutic fields have evolved into high-tech sectors using state of the art technology, muscle strength testing which is part of most routine physical examination is still widely performed by a mere manual operation on behalf of an examiner. Muscle strength is typically tested by asking the patient or individual to move actively against the examiner""s opposition (commonly called a make test) or to resist against the pressure of the examiner on a part of his/her body (commonly called a brake test) while the patient is asked to maintain a specific posture. The examiner is therefore able to subjectively judge the patient""s maximum force, as conventionally called isometric manual muscle testing (MMT). Because of the sensitivity provided by the examiner, this method enables the examiner to assign a grade to indicate the weakness of the muscular contraction and to judge the qualitative aspect of the contraction such as slight shaking, saw-teeth type of effort or the like.
The strength is typically subjectively quantified and graded on a conventional zero to five scale. Although there are no international established standards, the grading scale varies between no muscular contraction detected (0) and active movement against full resistance without evident fatigue corresponding to normal muscle strength (5). Many clinicians make further distinction by using plus or minus signs towards the stronger and weaker end of the scale respectively. Thus, a (4+) grade indicates good but not full strength while a (5xe2x88x92) grade means a trace of weakness.
During the procedure, for purpose of comparison, the unaffected limb of the patient is typically similarly tested. From the hereinabove description, it is quite evident that the common manual method of muscle testing is opened to a large proportion of subjectivity.
Not only is the evaluation potentially unreliable when performed by a same individual but also this problem is compounded in situations wherein different individuals may use different techniques to perform the same testing.
Accordingly, several attempts to standardize manual testing procedures have been made and the prior art shows various devices adapted to measure muscle strength. For the most part, prior art devices suffer from a set of disadvantages including lack of ergonomical features, cumbersomeness, inability to test particular muscles or groups of muscles, complexity, lack of portability, expensiveness and so forth. One major drawback associated with some of the prior art devices is their inability to isolate specific muscles or muscle groups needing to be tested. Also, in the clinical context prior art testers have often proven to be difficult and time consuming to adjust to the specific ergonomical characteristics of the patient.
In order to test various body parts the devices always need to be quickly repositioned, thus failing to provide a practical solution, as opposed to quick displacements of the examiner to support and test these various body parts. As a result, despite the obvious disadvantages of the subjective test of muscle strength, manual testing without instrumentation continues to be the predominant method used in the clinical setting. One of the predominant factors is the so far unequaled ergonomical support provided by the examiner""s hands since prior art devices, especially the handheld dynamometers (HHD), are often uncomfortable to the patient and unstable (as opposed to a stabilization provided by a hand-grip).
Accordingly, there exists a need for an improved objective muscle strength testing method and device that uses the comfort and the grip of the naked hand of the examiner as the only direct support assistance and/or resistance.
It is therefore a general object of the present invention to provide a muscle strength testing method and apparatus that obviates the above-noted disadvantages.
An advantage of the present invention is that the muscle strength testing method and apparatus enables testing of most muscles and group of muscles of a human body.
A further advantage of the present invention is that the muscle strength testing method and apparatus provides sufficient sensitivity to objectively detect anything ranging from extremely small forces or muscle effort (even when the patient is unable to displace his/her body part against natural gravity) to normal large forces generated by limb muscles.
Yet another advantage of the present invention is that the muscle strength testing method and apparatus remains essentially manual in practice and enables simultaneous qualitative subjective and quantitative objective testing of muscles without interfering on or modifying the test itself.
Advantages of the present invention include the fact that the present muscle strength testing method and apparatus is specifically configured so as to be easy to use in a manner closely akin to the testing that examiners such as physicians, therapists, athletic trainers, coaches and the like currently use.
The muscle strength testing method and apparatus can be readily positioned so as to test various muscles or groups of muscles without the need for elaborate attachment to the patient and thus provides for a time efficient solution. Also, the present muscle strength testing method and apparatus affords accurate measurements and repeatability in its strength indication from one test to the next.
The present muscle strength testing method and apparatus by allowing use of a method closely akin to the currently highly performed manual method allows the examiner to obtain both a conventional subjective evaluation of the muscle strength and a more objective dynamometric numerical value of the patient""s muscle strength. By allowing the hand of the examiner to provide for resistive forces during the strength evaluation process the muscle strength testing method and apparatus reduces set-up time consumption and sometimes complex set-up procedures.
Furthermore, the present muscle strength testing method and apparatus allows for the elimination of gravity induced biases and thus allows for the evaluation of even very weak muscles.
The present muscle strength testing method and apparatus provides various options such as the display of strength versus time curves, the recall of previous test values, the storage of various test values in electronic memory, the electronic linkage to various computing means for processing of the information.
Still further, the present muscle strength testing method and apparatus allows for measuring, recording and displaying of the strength of various muscles or groups of muscles and of strength peak values during effort.
Other objects and advantages of the present invention will become apparent from a careful reading of the detailed description provided herein, with appropriate reference to the accompanying drawings.
According to one aspect of the present invention, there is provided a muscle strength testing method for allowing an intended examiner to assess a muscular contraction of a selected muscle of a patient and the strength of the muscular contraction, the selected muscle being anatomically coupled to a target body part of the patients the patient further defining a patient non-target body part spaced from the patient target body part, the examiner having an examiner contacting body part for contacting the patient target body part and an examiner non-contacting body part spaced from the examiner contacting body part, the method allowing simultaneously the assessment of the muscular contraction of the selected muscle through direct contact between the examiner contacting body part and the patient target body part and the assessment of the strength of the muscular contraction of the selected muscle through the use of a pressure sensor, the method comprises the steps of positioning the pressure sensor so that the force exerted by the selected muscle during contraction thereof is transmitted indirectly to the pressure sensor without direct contact between the pressure sensor and the patient target body part; allowing the selected muscle to contract; allowing the examiner to assess by direct contact between the patient target body part and the examiner contacting body part the muscular contraction of the selected muscle and the strength of the muscular contraction; and providing a force value for the strength of said muscular contraction of the selected muscle through the use of the pressure sensor.
In one embodiment, the pressure sensor is positioned so as to be in contact with the examiner non-contacting body part, the force exerted by the selected muscle during contraction thereof being transmitted to the pressure sensor from the selected muscle to the patient target body part, from the patient target body part to the examiner contacting body part, from the examiner contacting body part to the examiner non-contacting body part and from the examiner non-contacting body part to the pressure sensor.
Typically, the method further comprises the step of: positioning a supporting component intermediate the examiner non-contacting body part and the pressure sensor so that the force exerted by the selected muscle during contraction thereof is transmitted from the examiner non-contacting body part to the supporting component and from the supporting component to the pressure sensor.
In one embodiment, the pressure sensor is positioned so as to be in contact with the patient non-target body part, the force exerted by the selected muscle during contraction thereof being transmitted to the patient target body part and from the patient target body part to the examiner contacting body part, the examiner contacting body part exerting an opposite reaction force on the patient target body part, the reaction force being generally equal to the selected muscle force, the reaction force being transmitted to the pressure sensor, from the patient target body part to the patient non-target body part, and from the patient non-target body part to the pressure sensor.
Typically, the method further comprises the step of: positioning a supporting component intermediate the patient non-target body part and the pressure sensor so that the reaction force exerted by the examiner contacting body part is transmitted from the patient non-target body part to the supporting component and from the supporting component to the pressure sensor.
Typically, the supporting component defines a body interfacing section and a sensor interfacing section, the body interfacing section supporting the patient non-target body part, and the sensor interfacing section contacting the pressure sensor.
In one embodiment, the sensor interfacing section includes at least two legs, and the pressure sensor includes at least two sensor devices, each of the sensor devices supporting a respective one of the legs, the force value corresponding to the strength of the selected muscle being provided through the use of the at least two sensor devices.
In one embodiment, the force value is evaluated by subtracting a first force value from a second force value transmitted indirectly to the pressure sensor, the first and second force values resulting from the contraction of the selected muscle while the selected muscle is respectively in a first and a second contracting state, the examiner contacting body part directly contacting the patient target body part during at least one of the first and second contracting states of the selected muscle.
Typically, the first contracting state is a relaxed state of the selected muscle, the first force value including a weight of at least a portion of said patient target body part; the examiner contacting body part applying an opposition to the force exerted by the selected muscle during muscular contraction thereof in the second contracting state on the patient target body part so as to substantially reduce movement of the patient target body part, the second force value including the weight of the at least a portion of the patient target body part; the step of providing a force value on the strength of the selected muscle through the use of the pressure sensor including: subtracting the first force value from the second force value so as to evaluate the force value for the strength of said muscular contraction of the selected muscle through the use of the pressure sensor, thereby canceling off the weight of the at least a portion of the patient target body part included in both the first and second force values.
In one embodiment, the method further includes the step of: positioning the patient target body part in a substantially horizontal orientation so that the force exerted by the selected muscle during contraction thereof is in a substantially vertical orientation.
In one embodiment, the pressure sensor is connectable to a computer member, the computer member including a display member connected thereto and a database, the database containing set-up data related to a plurality of muscles of the patient, the selected muscle being selectable from the plurality of muscles, the set-up data including information on positioning of the patient target body part, patient non-target body part, examiner contacting body part, examiner non-contacting body part and pressure sensor relative to each other for each one of the plurality of muscles, the method further includes the steps of: selecting the selected muscle from the plurality of muscles of the database of the computer member; displaying the set-up data information corresponding to the selected muscle on the display member; and displaying the force value for the strength of said muscular contraction of the selected muscle on the display member.
According to another aspect of the present invention, there is provided a muscle strength testing apparatus for allowing an intended examiner to assess a muscular contraction of a selected muscle of a patient and the strength of the muscular contraction, the selected muscle being anatomically coupled to a target body part of the patient, the patient further defining a patient non-target body part spaced from the patient target body part, the examiner having an examiner contacting body part for contacting the patient target body part and an examiner non-contacting body part spaced from the examiner contacting body part, the apparatus allowing the assessment of the muscular contraction of the selected muscle and the strength of the muscular contraction by the examiner through direct contact between the examiner contacting body part and the patient target body part, the apparatus comprises: a pressure sensor for sensing the strength of the muscular contraction of the selected muscle; a means for positioning the pressure sensor so that the force exerted by the selected muscle during contraction thereof is transmitted indirectly to the pressure sensor without direct contact between the pressure sensor and the patient target body part while allowing direct contact between the examiner contacting body part and the patient target body part; and a controller device connecting to the pressure sensor for providing information on the strength of the selected muscle through the use of the pressure sensor, the controller device assessing a force value transmitted to the pressure sensor and corresponding to the force exerted by the selected muscle.
Typically, the controller device includes an operator interface and a display member, the operator interface allowing an operator to activate the controller device, and the display member displaying the force value sensed by the pressure sensor.
In one embodiment, the pressure sensor includes at least two sensor devices, the force exerted by the selected muscle being transmitted to the at least two sensor devices, each of the sensor devices connecting to the controller device so that the controller device assesses the force value transmitted to the at least two sensor devices and resulting from the force exerted by the contraction of the selected muscle while the selected muscle.
In one embodiment, the force value is evaluated by subtracting a first force value from a second force value transmitted indirectly to the pressure sensor, the first and second force values resulting from the contraction of the selected muscle while the selected muscle is respectively in a first and a second contracting state, the controller device assessing the force value from the first and second force values transmitted to the pressure sensor and corresponding to the force exerted by the selected muscle while the selected muscle is respectively in the first and second contracting states.
Typically, the controller device includes an electronic circuit and a display member, the electronic circuit connecting to the pressure sensor for assessment of the first and second force values, the display member connecting to the electronic circuit to display the force value corresponding to the force exerted by the selected muscle and evaluated from the first and second force values.
In one embodiment, the electronic circuit assesses the first force value by averaging at least two first force value readings, the first force value readings being sensed by the pressure sensor over a pre-determined first time period during which the selected muscle is in the first contracting state. The second force value is a profiled force value occurring over a pre-determined second time period, the profiled second force value including at least two second force value readings, the electronic circuit assessing the second force value by subtracting the averaged first force value from each one of the second force value readings so as to provide a profiled force value for the strength of said muscular contraction of the selected muscle during contraction thereof.
Typically, the electronic circuit includes a storage memory, the storage memory storing the first and second force values.
In one embodiment, the controller device further includes a computer member connectable to the electronic circuit, the computer member including a database, the database containing set-up data related to a plurality of muscles of the patient, the selected muscle being selectable from the plurality of muscles, the set-up data including information on positioning of the patient target body part, patient non-target body part, examiner contacting body part, examiner non-contacting body part and pressure sensor relative to each other for each one of the plurality of muscles, the set-up data information being displayable on the display member.
In one embodiment, the controller device includes a remote activating switch connected thereto for remotely activating the controller device.
In one embodiment, the apparatus is portable.
In one embodiment, the means includes a supporting component adapted to be positioned intermediate the examiner non-contacting body part and the pressure sensor so that the force exerted by the selected muscle during contraction thereof is transmitted to the pressure sensor from the selected muscle to the patient target body part, from the patient target body part to the examiner contacting body part, from the examiner contacting body part to the examiner non-contacting body part, from the examiner non-contacting body part to the supporting component and from the supporting component to the pressure sensor.
In one embodiment, the means includes a supporting component adapted to be positioned intermediate the patient non-target body part and the pressure sensor so that the force exerted by the selected muscle during contraction thereof is transmitted to the pressure sensor from the selected muscle to the patient target body part, from the patient target body part to the examiner contacting body part, the examiner contacting body part exerting an opposite reaction force on the patient target body part, the reaction force being generally equal to the selected muscle force, the reaction force being transmitted to the pressure sensor, from the patient target body part to the patient non-target body part, from the patient non-target body part to the supporting component, and from the supporting component to the pressure sensor.